Can and can end indexing machines are well known in the art and a representative system is disclosed, for example in the Training and Service Manual for the Model No. 107 Can End post-Repair Spray Machine, manufactured and sold by the H. L. Fisher Manufacturing Co., Inc. of Des Plaines, Ill. As disclosed in the Training and Service Manual, the can end indexing machines are specifically designed to apply a protective spray coating on the product side of a tinplate or aluminum can end. Other relevant prior art is an alternative machine for indexing containers, i.e. cans, also manufactured and sold by the H L. Fisher Manufacturing Co., for indexing cans. This alternative machine, as illustrated in FIG. 11, is similar to the Model No. 107 machine except that the cans are vacuumed onto chucks which project outwardly from the face of the turret. A problem with these types of prior art can and can end indexing machines, such as the Model No. 170 machine, however, is that the rotating vacuum turret is designed for rotation only in a vertical plane which limits its versatility and usefulness in some manufacturing facilities where rotation in either the horizontal or vertical plane would be advantageous because of space considerations. Rotation in the horizontal plane is also advantageous because it facilitates easier loading and unloading of the cans. The Model No. 170 type machines do not show or suggest horizontal rotation because the feed and unloading assemblies require vertical orientation.
Another problem with the prior art systems was the inability to stack two or more vacuum turrets on a single indexing machine. Where several turrets are required, a separate indexing machine, along with its associated power lines, pressure lines and vacuum lines, is needed for each additional turret. Besides the additional expense of purchasing and installing a separate indexing machine for each turret, added floor space, machine operator time and maintenance are costly additions needed for operating each extra turret. The Model No. 170 type machines do not show or suggest stacking several turrets on a single machine.
Another problem with an indexing machine design having cans project outwardly from the face of the turret is that loading and unloading of the cans is somewhat difficult and awkward.